Air vents would help although how much depends on air flow. I'm all rural and on a hill so I get lots of N/S air movement through the open sides.
My neighbor parked his new motor home in a fully enclosed trailer shed. In about two years most of the plastic and exterior rubber/vinyl parts started to discolor and harden due to no ventilation.
Some thing to consider...... My son, in Florida, has a three bay enclosed building with 12' wide rool up doors per his town's code for his 36' 5er/26' blue water fisher/air boat/etc. The building has two powered thermostat controlled fans that suck the heat out.